Preparation of dixanthogens



Patented Jan. 20, 1942 PREPARATION OF DIXANTHOGENS George L. Browning, Jr., Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York No Drawing. Application December 18, 1940, Serial No. 370,684

4 Claims.

This invention relates to the preparation of dixanthogens, and has as its principal object the oxidation of an alkali metal xanthate with alkali metal hypochlorite under such conditions that good yields of a dixanthogen are obtained.

When alkali metal xanthates are oxidized to dixanthogens by means of an alkali metal hypochlorite and no attempt is made to remove the heat generated by the reaction, rather low yields of product are obtained. Even when an efficient cooling system is employed and the temperature is kept down to about C., no improvement in yield is observed. I have found that contrary to expectations, when the temperature is maintained in the approximate range of from -25 0., and preferably about C., higher yields of dixanthogen are obtained.

In one experiment, an aqueous solution of 29.8 gm. of sodium hypochlorite was placed in a dropping funnel and slowly added to an aqueous solution of 64.7 gm. of sodium isopropyl xanthate, the temperature of the reaction mixture being maintained between 15 and 20 C. The light yellow crystalline product was separated from the reaction mixture and dried. A 63% yield of pure diisopropyl dixanthogen was obtained. When the same oxidation was performed at a temperature below 10 C., the yields were decreased by more than 10%. Materially decreased yields were also obtained by performing the oxidation in the temperature range between 35 and 40 C.

Any alkali metal xanthate such as sodium ethyl xanthate, sodium n-propyl xanthate, sodium sec.-butyl xanthate, sodium act.-amyl xanthate, potassium cyclohexyl xanthate, potassium benzyl xanthate, etc. may be oxidized to the corresponding dixanthogen by the method of this invention. Any alkali metal hypochlorite may be employed, although sodium or potassium hypochlorite will ordinarily be selected for economic reasons.

The temperature may be maintained within the desired range by any desired method of cooling. Since the oxidation is performed in aqueous solution, it is convenient to cool the reaction mixture to 15-25 C. by merely adding ice, and to maintain the temperature within this range by adding more ice as needed during the course of the reaction.

Various modifications of the above procedure which will be apparent to those skilled in the art are within the spirit and scope of the invention as defined in the appended claims.

I claim:

1. The method of oxidizing an alkali metal xanthate to a dixanthogen which comprises adding an alkali metal hypochlorite to an aqueous solution of the xanthate and maintaining the temperature within the approximate range of from 15 to 25 C. throughout the oxidation.

2. The method of oxidizing a sodium xanthate to a dixanthogen which comprises adding sodium hypochlorite to an aqueous solution of the xanthate and maintaining the temperature within the approximate range of from 15 to 25 0. throughout the oxidation.

3. The method of oxidizing sodium isopropyl xanthate to diisopropyl dixanthogen which comprises adding sodium hypochlorite to an aqueous solution of the xanthate and maintaining the temperature within the approximate range of from 15 to 25 C. throughout the oxidation.

4. The method of oxidizing an alkali metal xanthate to a dixanthogen which comprises adding an alkali metal hypochlorite to an aqueous solution of the xanthate and maintaining the temperature at about 20 C. throughout the oxidation.

GEORGE L. BROWNING, JR. 

